//
// Created by Administrator on 2017/3/16 0016.
//
#include <libavutil/timestamp.h>
#include <libavformat/avformat.h>

static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag) {
    AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
    printf("%s: pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
           tag,
           av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
           av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
           av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
           pkt->stream_index);
}

int main(int argc, char **argv)
{
    AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
    AVOutputFormat *ofmt = NULL;
    AVPacket pkt;

    const char *in_filename, *out_filename;
    int ret, i;

    if (argc < 3) {
        printf("usage: %s input output\n"
                       "API example program to remux a media file with libavformat and libavcodec.\n"
                       "The output format is guessed according to the file extension.\n"
                       "\n", argv[0]);
        return 1;
    }

    in_filename = argv[1];
    out_filename = argv[2];

    av_register_all();

    // ------------------------------------------------------- Get input AVFormatContext

    if((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0)
    {
        fprintf(stderr, "Cannot open input file '%s'", in_filename);
        goto end;
    }

    if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0)
    {
        fprintf(stderr, "Cannot find stream info.");
        goto end;
    }

    av_dump_format(ifmt_ctx, 0, in_filename, 0);

    // ------------------------------------------------------- Create output AVFormatContext and set stream info
    avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
    if (!ofmt_ctx)
    {
        fprintf(stderr, "Could not create output context\n");
        ret = AVERROR_UNKNOWN;
        goto end;
    }

    ofmt = ofmt_ctx->oformat;

    // 根据输入文件的流，创建输出文件的流，并设置参数
    for (int j = 0; j < ifmt_ctx->nb_streams; ++j) {
        AVStream *in_stream = ifmt_ctx->streams[j];
        AVStream *out_stream = avformat_new_stream(
                ofmt_ctx, avcodec_find_encoder(AV_CODEC_ID_FLV1));
        if (!out_stream) {
            fprintf(stderr, "Failed to alloc output stream.\n");
            ret = AVERROR_UNKNOWN;
            goto end;
        }

        // 复制输入文件流编码器参数到输出文件流编码器
        ret = avcodec_parameters_copy(out_stream->codecpar, in_stream->codecpar);
        if (ret < 0)
        {
            fprintf(stderr, "Failed to copy codec parameters from input to output stream\n");
            goto end;
        }

        out_stream->codecpar->codec_tag = 0;

        if (ofmt->flags & AVFMT_GLOBALHEADER) {
            // Format wants global header
            ofmt->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
        }

    }

    av_dump_format(ofmt_ctx, 0, out_filename, 1);

    // ------------------------------------------------------- Open output i/o

    if (!(ofmt->flags & AVFMT_NOFILE)) {
        ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
        if (ret < 0) {
            fprintf(stderr, "Could not open output file '%s'\n", out_filename);
            goto end;
        }
    }

    // ------------------------------------------------------- Write data

    // -------- Write header
    ret = avformat_write_header(ofmt_ctx, NULL);
    if (ret < 0) {
        fprintf(stderr, "Error occurred when write header\n");
        goto end;
    }

    while (1)
    {
        AVStream *in_stream, *out_stream;

        ret = av_read_frame(ifmt_ctx, &pkt);
        if (ret < 0)
            break;

        in_stream = ifmt_ctx->streams[pkt.stream_index];
        out_stream = ofmt_ctx->streams[pkt.stream_index];

        log_packet(ifmt_ctx, &pkt, "in");

        // Copy packet
        pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base,
                                   AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX);
        pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base,
                                   AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX);
        pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
        pkt.pos = -1;

        log_packet(ofmt_ctx, &pkt, "out");

        ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
        if (ret < 0) {
            fprintf(stderr, "Error muxing packet\n");
            break;
        }
        av_packet_unref(&pkt);
    }

    // -------- Write trailer
    ret = av_write_trailer(ofmt_ctx);
    if (ret < 0) {
        fprintf(stderr, "Error occurred when write trailer\n");
        goto end;
    }

    // ------------------------------------------------------- END: release mem
    end:
    avformat_close_input(&ifmt_ctx);
    avformat_free_context(ifmt_ctx);
    avformat_free_context(ofmt_ctx);

    if (ret < 0 && ret != AVERROR_EOF) {
        fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
        return 1;
    }
    return 0;
}